Power management for touch controller

ABSTRACT

Power management for a touch controller is disclosed. The touch controller can include a transmit section for transmitting stimulation signals to an associated touch sensor panel to drive the panel, where the touch controller can selectively adjust the transmit section to reduce power during the transmission. The touch controller can also include a receive section for receiving touch signals resulting from the driving of the panel, where the touch controller can selectively adjust the receive section to reduce power during the receipt of the touch signals. The touch controller can also include a demodulation section for demodulating the received touch signals to obtain touch event results, where the touch controller can selectively adjust the demodulation section to reduce power during the demodulation of the touch signals. The touch controller can also selectively reduce power below present low levels during idle periods.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of Ser. No. 16/275,961,filed Feb. 14, 2019 (U.S. Patent Application Publication No.2019/0286220), which is a continuation application of Ser. No.15/260,257, filed Sep. 8, 2016 (now U.S. Pat. No. 10,222,854, issued onMar. 5, 2019), which is a divisional application of U.S. Ser. No.14/749,524, filed Jun. 24, 2015 (now U.S. Pat. No. 9,529,415, issuedDec. 27, 2016) which is a divisional application of U.S. patentapplication Ser. No. 14/600,973, filed Jan. 20, 2015 (now U.S. Pat. No.9,098,286, issued Aug. 4, 2015), which is a continuation application ofSer. No. 12/557,962, filed Sep. 11, 2009 (now U.S. Pat. No. 8,970,506,issued Mar. 3, 2015) all of which are hereby incorporated by referencein their entirety for all purposes.

FIELD

This relates generally to controllers for touch sensitive devices and,more particularly, to power management of controllers for touchsensitive devices.

BACKGROUND

Many types of input devices are presently available for performingoperations in a computing system, such as buttons or keys, mice,trackballs, joysticks, touch sensor panels, touch screens and the like.Touch sensitive devices, such as touch screens, in particular, arebecoming increasingly popular because of their ease and versatility ofoperation as well as their declining price. A touch sensitive device caninclude a touch sensor panel, which can be a clear panel with atouch-sensitive surface, and a display device such as a liquid crystaldisplay (LCD) that can be positioned partially or fully behind the panelso that the touch-sensitive surface can cover at least a portion of theviewable area of the display device. The touch sensitive device canallow a user to perform various functions by touching the touch sensorpanel using a finger, stylus or other object at a location dictated by auser interface (UI) being displayed by the display device. In general,the touch sensitive device can recognize a touch event and the positionof the touch event on the touch sensor panel, and the computing systemcan then interpret the touch event in accordance with the displayappearing at the time of the touch event, and thereafter can perform oneor more actions based on the touch event.

To achieve a certain ease and versatility of operation, touch sensitivedevices can have significant power requirements, which can be due to thecomponents required to operate the touch sensitive device as well as thefunctions performed on the device. Such power requirements canunfortunately lead to shorter battery usage between recharges, reducedfunctionality to conserve power, or larger touch sensitive devices tohouse more powerful power supplies.

SUMMARY

This relates to touch controller power management of a touch sensitivedevice. The touch controller can manage device power so as to reducepower consumption at certain times for the device. The touch controllercan selectively adjust bias current to components in a receive sectionof the device and/or can selectively bypass components in the receivesection to reduce power while processing touch events, where the receivesection can receive touch signals indicative of the touch events. Thetouch controller can also selectively adjust operating time ofcomponents in a demodulation section of the device and/or can selectdemodulation data to be used by components in the demodulation sectionto reduce power while processing touch events, where the demodulationsection can demodulate the touch signals received from the receivesection. The touch controller can selectively adjust slew rates ofcomponents in a transmit section of the device while processing touchevents, where the transmit section can provide stimulation signals tostimulate the device to generate the touch signals. The touch controllercan also selectively reduce power consumption below present low powerlevels during idle periods of the device. The power management canadvantageously provide power savings for the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary computing system having touch controllerpower management according to various embodiments.

FIG. 2 illustrates an exemplary touch controller having power managementaccording to various embodiments.

FIG. 3 illustrates an exemplary receive section of a touch controllerhaving power management according to various embodiments.

FIG. 4 illustrates another exemplary receive section of a touchcontroller having power management according to various embodiments.

FIG. 5 illustrates still another exemplary receive section of a touchcontroller having power management according to various embodiments.

FIG. 6 illustrates an exemplary method for power management of a receivesection of a touch controller according to various embodiments.

FIG. 7 illustrates an exemplary demodulation section of a touchcontroller having power management according to various embodiments.

FIG. 8 illustrates an exemplary method for power management of ademodulation section of a touch controller according to variousembodiments.

FIG. 9 illustrates an exemplary transmit section of a touch controllerhaving power management according to various embodiments.

FIG. 10 illustrates an exemplary method for power management of atransmit section of a touch controller according to various embodiments.

FIG. 11 illustrates an exemplary memory section of a touch controllerhaving power management according to various embodiments.

FIG. 12 illustrates an exemplary method for power management of a memorysection of a touch controller according to various embodiments.

FIGS. 13a-13e illustrate exemplary power diagrams for operating modes ofa system having touch controller power management according to variousembodiments.

FIG. 14 illustrates an exemplary composite power diagram for operatingmodes of a system having touch controller power management according tovarious embodiments.

FIG. 15 illustrates an exemplary state diagram for power managementduring operating modes of a system having touch controller powermanagement according to various embodiments.

FIG. 16 illustrates an exemplary lookup table for touch controller powermanagement according to various embodiments.

FIG. 17 illustrates an exemplary method for power management of a touchcontroller according to various embodiments.

FIG. 18 illustrates an exemplary mobile telephone having touchcontroller power management according to various embodiments.

FIG. 19 illustrates an exemplary digital media player having touchcontroller management according to various embodiments.

FIG. 20 illustrates an exemplary personal computer having touchcontroller power management according to various embodiments.

DETAILED DESCRIPTION

In the following description of various embodiments, reference is madeto the accompanying drawings which form a part hereof, and in which itis shown by way of illustration specific embodiments which can bepracticed. It is to be understood that other embodiments can be used andstructural changes can be made without departing from the scope of thevarious embodiments.

This relates to power management of a touch controller of a touchsensitive device. The touch controller can include power managementlogic to apply power adjustments to components of the device to reducepower. The power management logic can selectively apply bias currentadjustments and/or bypass commands to components of the touchcontroller's receive section configured to receive touch signals fromthe associated touch sensor panel. The power management logic canselectively apply time adjustments and/or demodulation data selection tocomponents of the touch controller's demodulation section configured todemodulate the touch signals received from the receive section. Thepower management logic can selectively apply slew rate adjustments tocomponents of the touch controller's transmit section configured toprovide stimulation signals to the associated touch sensor panel forgenerating the touch signals. The power management logic can selectivelyapply lower power consumption requirements to the device during idleperiods.

The touch controller power management can advantageously reduce powerconsumption of components in touch sensitive devices, which can resultin power savings in the devices. The power savings can be realized inlonger battery life, more robust functionalities that consume power,smaller power supplies, and smaller devices.

Although various embodiments can be described and illustrated herein interms of mutual capacitance touch sensor panels, it should be understoodthat the various embodiments are not so limited, but can be additionallyapplicable to self-capacitance sensor panels, and both single andmulti-touch sensor panels, and other sensors in which single stimulationsignals can be used to generate a touch signal and in which multiplesimultaneous stimulation signals can be used to generate a compositetouch signal. Furthermore, although various embodiments can be describedand illustrated herein in terms of double-sided ITO (DITO) touch sensorpanels, it should be understood that the various embodiments can be alsoapplicable to other touch sensor panel configurations, such asconfigurations in which the drive and sense lines can be formed ondifferent substrates or on the back of a cover glass, and configurationsin which the drive and sense lines can be formed on the same side of asingle substrate.

FIG. 1 illustrates an exemplary computing system 100 that can have touchcontroller power management according to various embodiments describedherein. In the example of FIG. 1, computing system 100 can include touchcontroller 106. The touch controller 106 can be a single applicationspecific integrated circuit (ASIC) that can include one or moreprocessor subsystems 102, which can include one or more main processors,such as ARM968 processors or other processors with similar functionalityand capabilities. However, in other embodiments, the processorfunctionality can be implemented instead by dedicated logic, such as astate machine. The processor subsystems 102 can also include peripherals(not shown) such as random access memory (RAM) or other types of memoryor storage, watchdog timers and the like. The touch controller 106 canalso include receive section 107 for receiving signals, such as touchsignals 103 of one or more sense channels (not shown), other signalsfrom other sensors such as sensor 111, etc. The touch controller 106 canalso include demodulation section 109 such as a multistage vectordemodulation engine, panel scan logic 110, and transmit section 114 fortransmitting stimulation signals 116 to touch sensor panel 124 to drivethe panel. The panel scan logic 110 can access RAM 112, autonomouslyread data from the sense channels, and provide control for the sensechannels. In addition, the panel scan logic 110 can control the transmitsection 114 to generate the stimulation signals 116 at variousfrequencies and phases that can be selectively applied to rows of thetouch sensor panel 124.

The touch controller 106 can also include charge pump 115, which can beused to generate the supply voltage for the transmit section 114. Thestimulation signals 116 can have amplitudes higher than the maximumsupply voltage by cascading two charge store devices, e.g., capacitors,together to form the charge pump 115. Although FIG. 1 shows the chargepump 115 separate from the transmit section 114, the charge pump can bepart of the transmit section.

The touch controller 106 can also include power management logic 145,which can be used to manage power consumption by various components ofthe controller. The power management logic 145 can access the processorsubsystem 102, the receive section 107, the demodulation section 109,the panel scan logic 110, the RAM 112, and the transmit section 114,autonomously receive data from and send data to these components via,for example, power management signals 146, and manage power consumptionof these components. The power management logic 145 can be partially orentirely part of or separate from the processor subsystem 102.Alternatively, the power management logic 145 can be implementedpartially or entirely in dedicated logic, such as a state machine.

Touch sensor panel 124 can include a capacitive sensing medium havingrow traces (e.g., drive lines) and column traces (e.g., sense lines),although other sensing media can also be used. The row and column tracescan be formed from a transparent conductive medium such as Indium TinOxide (ITO) or Antimony Tin Oxide (ATO), although other transparent andnon-transparent materials such as copper can also be used. In someembodiments, the row and column traces can be perpendicular to eachother, although in other embodiments other non-Cartesian orientationsare possible. For example, in a polar coordinate system, the sense linescan be concentric circles and the drive lines can be radially extendinglines (or vice versa). It should be understood, therefore, that theterms “row” and “column” as used herein are intended to encompass notonly orthogonal grids, but the intersecting traces of other geometricconfigurations having first and second dimensions (e.g. the concentricand radial lines of a polar-coordinate arrangement). The rows andcolumns can be formed on, for example, a single side of a substantiallytransparent substrate separated by a substantially transparentdielectric material, on opposite sides of the substrate, on two separatesubstrates separated by the dielectric material, etc.

At the “intersections” of the traces, where the traces pass above andbelow (cross) each other (but do not make direct electrical contact witheach other), the traces can essentially form two electrodes (althoughmore than two traces can intersect as well). Each intersection of rowand column traces can represent a capacitive sensing node and can beviewed as picture element (pixel) 126, which can be particularly usefulwhen the touch sensor panel 124 is viewed as capturing an “image” oftouch. (In other words, after the touch controller 106 has determinedwhether a touch event has been detected at each touch sensor in thetouch sensor panel, the pattern of touch sensors in the multi-touchpanel at which a touch event occurred can be viewed as an “image” oftouch (e.g. a pattern of fingers touching the panel).) The capacitancebetween row and column electrodes can appear as a stray capacitanceCstray when the given row is held at direct current (DC) voltage levelsand as a mutual signal capacitance Csig when the given row is stimulatedwith an alternating current (AC) signal. The presence of a finger orother grounded conductive object near or on the touch sensor panel canshunt some of the electric field between the row and column electrodesto ground, which can cause Csig to decrease. This decrease can in turncause a signal charge Qsig present at the pixels being touched todecrease, where Qsig can be the product of Csig multiplied by thestimulation signal amplitude. Therefore, the distance between a groundedobject, such as a finger, and a touched pixel can be related to thelevel of Qsig.

Computing system 100 can also include host processor 128 for receivingoutputs from the processor subsystems 102 and performing actions basedon the outputs that can include, but are not limited to, moving anobject such as a cursor or pointer, scrolling or panning, adjustingcontrol settings, opening a file or document, viewing a menu, making aselection, executing instructions, operating a peripheral deviceconnected to the host device, answering a telephone call, placing atelephone call, terminating a telephone call, changing the volume oraudio settings, storing information related to telephone communicationssuch as addresses, frequently dialed numbers, received calls, missedcalls, logging onto a computer or a computer network, permittingauthorized individuals access to restricted areas of the computer orcomputer network, loading a user profile associated with a user'spreferred arrangement of the computer desktop, permitting access to webcontent, launching a particular program, encrypting or decoding amessage, and/or the like. The host processor 128 can also performadditional functions that may not be related to panel processing, andcan be coupled to program storage 132 and display device 130 such as anLCD display for providing a UI to a user of the device. In someembodiments, the host processor 128 can be a separate component from thetouch controller 106, as shown. In other embodiments, the host processor128 can be included as part of the touch controller 106. In still otherembodiments, the functions of the host processor 128 can be performed bythe processor subsystem 102 and/or distributed among other components ofthe touch controller 106. The display device 130 together with the touchsensor panel 124, when located partially or entirely under the touchsensor panel or when integrated with the touch sensor panel, can form atouch sensitive device such as a touch screen.

Note that one or more of the functions described above can be performed,for example, by firmware stored in memory (e.g., one of the peripherals)and executed by the processor subsystem 102, or stored in the programstorage 132 and executed by the host processor 128. The firmware canalso be stored and/or transported within any computer readable storagemedium for use by or in connection with an instruction execution system,apparatus, or device, such as a computer-based system,processor-containing system, or other system that can fetch theinstructions from the instruction execution system, apparatus, or deviceand execute the instructions. In the context of this document, a“computer readable storage medium” can be any medium that can contain orstore the program for use by or in connection with the instructionexecution system, apparatus, or device. The computer readable storagemedium can include, but is not limited to, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatusor device, a portable computer diskette (magnetic), a random accessmemory (RAM) (magnetic), a read-only memory (ROM) (magnetic), anerasable programmable read-only memory (EPROM) (magnetic), a portableoptical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flashmemory such as compact flash cards, secured digital cards, USB memorydevices, memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport medium can include, but is not limited to, anelectronic, magnetic, optical, electromagnetic or infrared wired orwireless propagation medium.

It is to be understood that the touch sensor panel is not limited totouch, as described in FIG. 1, but can be a proximity panel or any otherpanel according to various embodiments. In addition, the touch sensorpanel described herein can be either a single-touch or a multi-touchsensor panel.

It is further to be understood that the touch controller is not limitedto the components and configuration of FIG. 1, but can include otherand/or additional components in various configurations capable of powermanagement according to various embodiments.

FIG. 2 illustrates an exemplary touch controller having power managementaccording to various embodiments. In the example of FIG. 2, touchcontroller 106 can include receive section 107, which can include atotal of N receive channels, such as sense channels 207. The sensechannels 207 can receive touch signals (illustrated by N inputs in FIG.2) from sense lines of an associated touch sensor panel indicative of atouch or near touch at the panel, for example. The sense channels 207can connect to power management lookup table (LUT) 254 for receiving LUTdata to manage power consumption. Each sense channel 207 can include areceive analog-to-digital converter (ADC) (not shown) to convert theanalog touch signals to digital touch signals for further processing.

The touch controller 106 can also include demodulation section 109 fordemodulating the touch signals from the receive section 107. Thedemodulation section 109 can include digital demodulator 213, resultmemory 215, and vector operator 217. The digital demodulator 213 canconnect to receive numerically-controlled oscillator (NCO) 219 for phaseand frequency data, to the power management LUT 254 for receiving LUTdata to manage power consumption, and to the receive section 107 forreceiving digital touch signals. The result memory 215 can save thedemodulated touch signals for further processing. The vector operator217 can connect to decode matrix RAM 221 for receiving data to decodethe touch signals into signal capacitance Csig values and to result RAM223 for saving the Csig values for further processing.

The touch controller 106 can also include transmit section 114, whichcan include transmit logic 227, transmit digital-to-analog converter(DAC) 229, and a total of M transmit channels such as drive channels233. The transmit logic 227 can connect to transmit NCO 235 for phaseand frequency data and to charge pump 115 for power to the drivechannels 233. The transmit DAC 229 can convert digital signals from thetransmit logic 227 into analog signals to the drive channels 233. Thedrive channels 233 can connect to stimulation matrix RAM 237 forreceiving data to generate stimulation signals (illustrated by M outputsin FIG. 2) to stimulate drive lines of the associated touch sensorpanel, for example. The drive channels 233 can also connect to the powermanagement LUT 254 for receiving LUT data to manage power consumption.

The touch controller 106 can also include processor subsystem 102, clockgenerator 243, panel scan logic 110, and processor interface 247, whichcan connect via bus 249 to other components of the controller. Theprocessor subsystem 102 can store and update, for example, decode datain a decode matrix on the decode matrix RAM 221, stimulation data in astimulation matrix on the stimulation matrix RAM 237, and LUT data inthe power management LUT 254. The processor subsystem 102 can furtherinitialize the system, process data from the sense channels 207, andfacilitate communication with the host processor 128. The clockgenerator 243 can provide clock data. The panel scan logic 110 canaccess RAM 112, autonomously read data from the sense channels 207, andprovide control for the sense channels and for the drive channels 233.The processor interface 247 can provide an interface for the hostprocessor 128.

The touch controller 106 can also include power management logic 145 formanaging power consumption of various components of the system. Thepower management logic 145 can access the power management LUT 254 viathe bus 249 and can store and update the LUT data. The power managementlogic 145 can be included either partially or entirely in or separate,e.g., as a state machine, from the processor subsystem 102.

The decode matrix RAM 221, the result RAM 223, and the stimulationmatrix RAM 237 can be part of the RAM 112, for example, in the touchcontroller 106. The power management LUT 254 can be stored in the RAM112, for example.

In an example operation, the transmit section 114 of the touchcontroller 106 can perform as follows. The transmit logic 227, which canbe powered by the charge pump 115, can generate digital signals based onthe transmit NCO 235. The transmit DAC 229 can convert the digitalsignals into stimulation signals and transmit the stimulation signals tothe drive channels 233. The drive channels 233 can transmit thestimulation signals to corresponding drive lines of the associated touchsensor panel. The phases (and/or other signal parameters) of thestimulation signals transmitted by the drive channels 233 can be setbased on data in the stimulation matrix stored in the stimulation matrixRAM 237. The panel scan logic 110 can control the timing of thestimulation signal transmissions to the drive lines. The panel scanlogic 110 can also modify the data in the stimulation matrix. The powerconsumption of the drive channels 233 can be managed based on data inthe power management LUT 254. The power management logic 145 can controlthe data sent from the LUT 254 to the drive channels 233.

As the drive channels 233 drive the drive lines of the associated touchsensor panel, the panel can sense a change in capacitance oncorresponding sense lines of the panel as a result of a touch or neartouch at the panel. Touch signals can be generated as a function of thecapacitance change and transmitted along the sense lines to the receivesection 107 of the touch controller 106. The panel scan logic 110 cancontrol the scanning of the panel in order to transmit the touch signalsto the receive section 107.

The receive section 107 of the touch controller 106 can perform asfollows. The sense channels 207 can receive the touch signals from theassociated touch sensor panel. The power consumption of the sensechannels 207 can be managed based on data in the power management LUT254. The power management logic 145 can control the data sent from theLUT 254 to the sense channels 207. The sense channels 207 can convertthe received touch signals to digital signals and transmit the digitalsignals to the demodulation section 109 for further processing.

The demodulation section 109 of the touch controller 106 can perform asfollows. The digital demodulator 213 can demodulate the digital signalsfrom the sense channels 207 by multiplying the signals with ademodulation signal of the same frequency generated by the receive NCO219. The power consumption of the demodulator 213 can be managed basedon data in the power management LUT 254. The power management logic 145can control the data sent from the LUT 254 to the demodulator 213. Theresult memory 215 can store the demodulated touch signals for furtherprocessing. Because multiple drive lines of the touch sensor panel canbe driven at a time, each generated touch signal can be a composite ofmultiple signal capacitances sensed by each sense line's pixels in thepanel. As such, a determination can be made from the composite of pixelcapacitances on each sense channel 207, e.g., by the vector operator217. The vector operator 217 can apply data in the decode matrix in thedecode matrix RAM 221 to the demodulated touch signals from the resultmemory 215 to obtain the pixel capacitances for each sense channel 207.The result RAM 223 can store the sense channel capacitances for sensingtouch or near touch at the panel, for example, using the processorsubsystem 102, the host processor 128, and so on.

It is to be understood that the touch controller is not limited to thecomponents, configuration, and operation described here in FIG. 2, butcan include other and/or additional components, configurations, and/oroperations capable of power management according to various embodiments.

FIG. 3 illustrates an exemplary receive section of a touch controllerhaving power management according to various embodiments. FIG. 3illustrates the details of one of the sense channels 207 in the receivesection 107 of the touch controller 106. In the example of FIG. 3,receive section 107 of touch controller 106 can include sense channel207 having multiplexer 301, transimpedence amplifier (TIA) 303, bandpassfilter (BPF) 305, anti-alias filter (AAF) 307, and analog-to-digitalconverter (ADC) 309. The multiplexer 301 can select from one or moretouch signal inputs from sense lines to the sense channel. Thetransimpedence amplifier 303 can convert the touch signal into a voltagesignal. The output of the amplifier 303 can be fed to the bandpassfilter 305 to reject noise components outside a particular band, e.g.,components far from the fundamental frequency of the signal, about ±30kHz in some embodiments. The output of the bandpass filter 305 can befed to the anti-alias filter 307 to attenuate noise components above thenyquist sampling limit of the receive ADC 309 sufficiently to preventthose noise components from aliasing back into the operating frequencyrange of the touch controller 106 and to improve the signal-to-noiseratio (SNR). The output of the anti-alias filter 307 can be converted bythe receive ADC 309 into a digital signal, which can be sent from thereceive section 107 to the demodulation section 109 for furtherprocessing.

The frequency of the stimulation signals (and consequently the frequencyof the generated touch signals) can affect the amount of noise in thetouch signal. The noise can be from internal sources, external sources,or both. Noise can be generated internally by, e.g., feedback resistorRfb of the transimpedence amplifier 303 and can vary according to aselected frequency. The gain Gtia of the amplifier 303 can vary with theselected frequency as follows, G_(tia)=ω_(stm)·r_(fb)·C_(sig), whereωstm=the stimulation signal frequency in radians; and rfb=the resistanceof the feedback resistor Rfb. To keep the gain Gtia constant, resistorRfb can be adjusted. For example, for a given target gain Gtia, if thestimulation signal frequency wstm is decreased by a factor of 2, thefeedback resistance rfb can be increased by a factor of 2 in order tomaintain the target gain. Since internal noise introduced by thefeedback resistor Rfb can be proportional to √{square root over(r_(fb))} for a given signal bandwidth, the internal noise can generallybe higher at lower stimulation signal frequencies. In contrast tointernal noise, the amount of external noise introduced into the touchsignal can be arbitrary and dependent on environmental conditions.

Certain frequencies can produce higher noise amounts than others. Thesense channels 207 can operate to reduce noise in the touch signal andto reduce noise contributions from the sense channel componentsthemselves. Higher noise amounts can result in higher power consumptionbecause the components can operate a higher level to reduce more noise.Conversely, lower noise amounts can result in lower power consumptionbecause the components can operate at a lower level to reduce lessnoise. As a result, the components' power consumption can be affected bythe frequency. Accordingly, power requirements can be determined forvarious frequencies associated with corresponding noise levels, therebyavoiding higher power consumption during lower noise conditions.

Table 1 shows examples of the relationships of internal and external SNRparameters to frequency and bias current level as follows.

TABLE 1 Example SNR Relationships. SNR Headroom for Bias CurrentInternal Total external noise Frequency Level SNR (dB) SNR (dB)(NZ_HDRM) (dB) FT_1 IB_1 63 60 3 FT_2 IB_2 66 60 6 FT_3 IB_3 67 60 7FT_4 IB_4 70 60 10

As shown in the table, the internal SNR can be known for a particularfrequency (FT) and bias current level (IB) of a sense channel in thereceive section of the touch controller. The SNR headroom for externalnoise (NZ_HDRM) can be calculated as the internal SNR minus the maximumallowable total SNR of the sense channel. In this example, the total SNRcan be 60 dB. As such, in the absence of external noise, the frequency(FT_1) and the bias current level (IB_1) can be selected because theexternal noise SNR of 0 would be lower than the SNR headroom of 3 dB atthis frequency and bias current level. Similarly, if an SNR headroom of5 dB is acceptable, the frequency (FT_2) and the bias current level(IB_2) can be selected because the acceptable SNR headroom would belower than the SNR headroom of 6 dB at this frequency and bias currentlevel.

Power management LUT 354 can include data that can be used to managepower consumption of the components of the receive section 107. In theexample of FIG. 3, the power management LUT 354 can include bias currentadjustments to the amplifier 303, the bandpass filter 305, theanti-alias filter 307, and the receive ADC 309 that can be appliedthereto during lower noise conditions, for example, so as to reducepower consumption to one or more of these components. Lower noiseconditions can require less noise reduction and, hence, less noisereduction operation from the sense channels of the receive section 107.

Table 2 shows an example power management LUT 354 as follows,

TABLE 2 Power Management Lookup Table Example DPPC[0] IADJ_TIA[0]IADJ_BPF [0] IADJ_AAF[0] IADJ_ADC[0] DPPC[1] IADJ_TIA[1] IADJ_BPF [1]IADJ_AAF[1] IADJ_ADC[1]

DPPC[n] IADJ_TIA[n] IADJ_BPF[n] IADJ_AAF[n] IADJ_ADC[n]

where DPPC=the numerical control input to the receive NCO that canrepresent a phase increment proportional to the touch signal frequency;IADJ_TIA=the bias current adjustment for the transimpedence amplifier;IADJ_BPF=the bias current adjustment for the bandpass filter;IADJ_AAF=the bias current adjustment for the anti-alias filter; andIADJ_ADC=the bias current adjustment for the analog-to-digitalconverter.

In an example, the LUT 354 can include n entries, where n=13, and wherethe phase increment (DPPC) can be 1024 to 13312 at increments of 1024with corresponding touch signal frequencies from 62.5 kHz to 812.5 kHzat increments of 62.5 kHz. For example, at an identified touch signalfrequency of 62.5 kHz, the phase increment of 1024 can be found in theLUT 354 and the corresponding bias current adjustment values can beapplied to the components of the receive section 107 to manage powerconsumption, e.g., to reduce the power to the components, whileproviding an acceptable touch signal quality.

Power management logic 145 can control which entry in the LUT 354 toselect to manage power consumption of the receive section 107. At aparticular touch signal frequency, the power management logic 145 canidentify the phase increment and select the corresponding bias currentadjustments from the LUT 354 to be applied to the components of thereceive section 107 in order to manage their power consumption.

In an example operation, the power management logic 145 can identifyphase increment 364 corresponding to the incoming touch signal frequencyand select from the LUT 354 the bias current adjustment to be made toone or more of the components in order to manage the power consumptionof that component. The amplifier 303 can receive the touch signal andconvert the touch signal to a voltage signal at a power level adjustedby bias current adjustment 313. The bandpass filter 305 can receive thevoltage signal and attenuate the signal noise at a power level adjustedby bias current adjustment 315. The anti-alias filter 307 can receivethe bandpass-filtered signal and further attenuate the signal noise at apower level adjusted by bias current adjustment 317. The receive ADC 309can receive the anti-aliased signal and convert the signal to a digitalsignal at a power level adjusted by bias current adjustment 319.

The bias current adjustments can be from low to high or any combinationthereof, depending on the noise conditions and the noise reductioncapabilities of the components. In some embodiments, there can be anoise threshold, for example at a given phase increment, which candefine an upper limit of the amount of noise tolerable in the touchsignal. As such, the bias current adjustments can be configured so as toallow noise to reach but not exceed that noise threshold. For example,it can be determined that the current to the bandpass filter can beadjusted to low for a given phase increment in order to reduce thefilter's noise reduction operation while not exceeding the noisethreshold.

For simplicity, FIG. 3 illustrates the details of one sense channel ofthe receive section. The receive section can have multiple sensechannels with similar components. As such, the power management LUT canhave a bias current adjustment for each component in each sense channelat each phase increment. The power management LUT can alternatively havethe same bias current adjustment for corresponding components in thesense channels, e.g., the same bias current adjustment for all theamplifiers, at each phase increment. The power management LUT canalternatively have individual bias current adjustments for somecomponents and the same bias current adjustments for other components ateach phase increment

The LUT can be updated dynamically to correspond to changing operatingconditions. The LUT can also be updated prior to operation for staticoperating conditions.

In an alternate embodiment, the power management LUT 354 can includebias current adjustments based on the SNR headroom of the externalnoise. Table 3 shows an example power management LUT 354 as follows,

TABLE 3 Power Management Lookup Table Example. NZ_HDRM IADJ_TIA IADJ_BPFIADJ_AAF IADJ_ADC [0] [0] [0] [0] [0] NZ_HDRM IADJ_TIA IADJ_BPF IADJ_AAFIADJ_ADC [1] [1] [1] [1] [1]

NZ_HDRM IADJ_TIA IADJ_BPF IADJ_AAF IADJ_ADC [n] [n] [n] [n] [n]

FIG. 4 illustrates another exemplary receive section of a touchcontroller having power management according to various embodiments.FIG. 4 illustrates the details of one of the sense channels 207 in thereceive section 107 of the touch controller 106. In the example of FIG.4, receive section 107 of touch controller 106 can include sense channel207 having multiplexer 401, transimpedence amplifier (TIA) 403, bandpassfilter (BPF) 405, anti-alias filter (AAF) 407, and analog-to-digitalconverter (ADC) 409. The operation of these components can be similar tothose in FIG. 3. In the example of FIG. 4, the sense channel can alsoinclude multiplexers 404-a, 404-b, 406-a, and 406-b. The multiplexers404-a and 404-b can select whether to bypass the bandpass filter 405 orto allow the bandpass filter to process the voltage signal from theamplifier 403. The bandpass filter 405 can receive a command to powerdown if bypassed. The multiplexers 406-a and 406-b can select whether tobypass the anti-alias filter 407 or to allow the anti-alias filter toprocess either the outputted signal from the bandpass filter 405 or thesignal that bypassed the bandpass filter. The anti-alias filter 407 canreceive a command to power down if bypassed.

Power management LUT 454 can include data that can be used to managepower consumption of the components of the receive section 107. In theexample of FIG. 4, the power management LUT 354 can include bypasscommands to the bandpass filter 405 and the anti-alias filter 407 thatcan be applied thereto during lower noise conditions so as to reducepower consumption to either or both of these components. Lower noiseconditions can require less noise reduction and, hence, less noisereduction operation from the sense channels of the receive section 107.

Table 4 shows an example power management LUT 454 as follows,

TABLE 4 Power Management Lookup Table Example DPPC[0] BYP_BPF[0]BYP_AFF[0] DPPC[1] BYP_BPF[1] BYP_AFF[1]

DPPC[n] BYP_BPF[n] BYP_AFF[n]

where DPPC=the numerical control input to the receive NCO that canrepresent a phase increment proportional to the touch signal frequency;BYP_BPF=the bypass command for the bandpass filter; and BYP_AAF=thebypass command for the anti-alias filter.

Power management logic 145 can control which entry in the LUT 454 toselect to manage power consumption of the receive section 107. At aparticular touch signal frequency, the power management logic 145 canidentify the phase increment (DPPC) and select the corresponding bypasscommands from the LUT 454 to be applied to the components of the receivesection 107 in order to manage their power consumption.

In an example operation, the power management logic 145 can identifyphase increment 464 corresponding to the incoming touch signal frequencyand select from the LUT 454 the bypass command to be made to either orboth the bandpass filter 405 and the anti-alias filter 407 in order tomanage the power consumption of that component. The amplifier 403 canreceive the touch signal and convert the touch signal to a voltagesignal. The bandpass filter 405 and the multiplexers 404-a and 404-b canreceive bypass command 415. If the bypass command 415 is to bypass andpower down the bandpass filter 405, the multiplexers 404-a and 404-b canbypass the bandpass filter with the voltage signal from the amplifier403 and the bandpass filter can power down. If the bypass command 415 isnot to bypass and power down the bandpass filter 405, the multiplexer404-a can transmit the voltage signal from the amplifier 403 to thebandpass filter to attenuate the signal noise and the multiplexer 404-bcan transmit the bandpass-filtered signal from the bandpass filter. Theanti-alias filter 407 and the multiplexers 406-a and 406-b can receivebypass command 417. If the bypass command 417 is to bypass and powerdown the anti-alias filter 407, the multiplexers 406-a and 406-b canbypass the anti-alias filter with the incoming signal and the anti-aliasfilter can power down. If the bypass command 417 is not to bypass andpower down the anti-alias filter 407, the multiplexer 406-a can transmitthe incoming signal to the anti-alias filter to further attenuate thesignal noise and the multiplexer 406-b can transmit the anti-aliasedsignal from the anti-alias filter. The receive ADC 409 can convert theincoming signal to a digital signal.

The bypass commands can be one on and one off, both off, or both on,depending on the noise conditions and the noise reduction capabilitiesof the components. In some embodiments, there can be a noise threshold,for example at a given phase increment, which can define an upper limitof the amount of noise tolerable in the touch signal. As such, thebypass commands can be configured to either on or off so as to allownoise to reach but not exceed that noise threshold. For example, it canbe determined that the bandpass filter can be bypassed and powered downfor a given phase increment in order to reduce the filter's noisereduction operation while not exceeding the noise threshold.

For simplicity, FIG. 4 illustrates the details of one sense channel ofthe receive section. The receive section can have multiple sensechannels with similar components. As such, the power management LUT canhave a bypass command for each component in each sense channel for eachphase increment. The power management LUT can alternatively have thesame bypass command for corresponding components in the sense channels,e.g., the same bypass command for all the bandpass filters, for eachphase increment. The power management LUT can alternatively haveindividual bypass commands for some components and the same bypasscommands for other components for each phase increment.

FIG. 5 illustrates still another exemplary receive section of a touchcontroller having power management according to various embodiments.FIG. 5 illustrates the details of one of the sense channels 207 in thereceive section 107 of the touch controller 106. In the example of FIG.5, receive section 107 of touch controller 106 can include thecomponents of FIGS. 3 and 4 and their respective bias currentadjustments and bypass commands. The operation of these components canbe similar to that in FIGS. 3 and 4.

Power management LUT 554 can include data that can be used to managepower consumption of the components of the receive section 107. In theexample of FIG. 5, the power management LUT 554 can include bias currentadjustments to the amplifier 503, the bandpass filter 505, theanti-alias filter 507, and the receive ADC 509, and bypass commands tothe bandpass filter 305 and the anti-alias filter 307 that can beapplied thereto during lower noise conditions so as to reduce powerconsumption to one or more of these components. Lower noise conditionscan require less noise reduction and, hence, less noise reductionoperation from the sense channels of the receive section 107.

Table 5 shows an example power management LUT 554 as follows,

TABLE 5 Power Management Lookup Table Example DPPC[0] IADJ_TIA[0]IADJ_BPF[0] IADJ_AAF[0] IADJ_ADC[0] BYP_BPF[0] BYP_AFF[0] DPPC[1]IADJ_TIA[1] IADJ_BPF[1] IADJ_AAF[1] IADJ_ADC[1] BYP_BPF[1] BYP_AFF[1]  

   

   

   

   

   

   

  DPPC[n] IADJ_TIA[n] IADJ_BPF[n] IADJ_AAF[n] IADJ_ADC[n] BYP_BPF[n]BYP_AFF[n]

where DPPC=the numerical control input to the receive NCO that canrepresent a phase increment proportional to the touch signal frequency;IADJ_TIA=the bias current adjustment for the transimpedence amplifier;IADJ_BPF=the bias current adjustment for the bandpass filter;IADJ_AAF=the bias current adjustment for the anti-alias filter;IADJ_ADC=the bias current adjustment for the analog-to-digitalconverter; BYP_BPF=the bypass command for the bandpass filter; andBYP_AAF=the bypass command for the anti-alias filter.

Power management logic 145 can control which entry in the LUT 554 toselect to manage power consumption of the receive section 107. At aparticular touch signal frequency, the power management logic 145 canidentify the phase increment (DPPC) and select the corresponding biascurrent adjustments and bypass commands from the LUT 554 to be appliedto the components of the receive section 107 in order to manage theirpower consumption.

In an example operation, the power management logic 145 can identifyphase increment 564 corresponding to the incoming touch signal frequencyand select from the LUT 554 the bias current adjustment and the bypasscommand to be made by the components in order to manage the powerconsumption of that component. The amplifier 503 can receive the touchsignal and convert the touch signal to a voltage signal at a power leveladjusted by bias current adjustment 513. The bandpass filter 505 and themultiplexers 504-a and 504-b can receive bypass command 514. If thebypass command 514 is to bypass and power down the bandpass filter 505,the multiplexers 504-a and 504-b can bypass the bandpass filter with thevoltage signal from the amplifier 503 and the bandpass filter can powerdown. If the bypass command 514 is not to bypass and power down thebandpass filter 505, the multiplexer 504-a can transmit the voltagesignal from the amplifier 503 to the bandpass filter to attenuate thesignal noise at a power level adjusted by bias current adjustment 515and the multiplexer 404-b can transmit the bandpass-filtered signal fromthe bandpass filter. The anti-alias filter 507 and the multiplexers506-a and 506-b can receive bypass command 516. If the bypass command516 is to bypass and power down the anti-alias filter 507, themultiplexers 506-a and 506-b can bypass the anti-alias filter with theincoming signal and the anti-alias filter can power down. If the bypasscommand 516 is not to bypass and power down the anti-alias filter 507,the multiplexer 506-a can transmit the incoming signal to the anti-aliasfilter to further attenuate the signal noise at a power level adjustedby bias current adjustment 517 and the multiplexer 506-b can transmitthe anti-aliased signal from the anti-alias filter. The receive ADC 509can convert the incoming signal to a digital signal at a power leveladjusted by bias current adjustment 519.

The bias current adjustments can be from low to high or any combinationthereof, depending on the noise conditions and the noise reductioncapabilities of the components. The bypass commands can be one on andone off, both off, or both on, depending on the noise conditions and thenoise reduction capabilities of the components. In some embodiments,there can be a noise threshold, for example at a given phase increment,which can define an upper limit of the amount of noise tolerable in thetouch signal. As such, the bias current adjustments and the bypasscommands can be configured so as to allow noise to reach but not exceedthat noise threshold. For example, it can be determined that thebandpass filter can be bypassed and powered down and the current to theanti-alias filter reduced for a given phase increment in order to reducetheir noise reduction operation while not exceeding the noise threshold.

For simplicity, FIG. 5 illustrates the details of one sense channel ofthe receive section. The receive section can have multiple sensechannels with similar components. As such, the power management LUT canhave a bias current adjustment and/or bypass command for each componentin each sense channel for a given phase increment. The power managementLUT can alternatively have the same bias current adjustments and/orbypass commands for corresponding components in the sense channels,e.g., the same bias current adjustment can be used for all theamplifiers, for a given phase increment. The power management LUT canalternatively have individual bias current adjustments and/or bypasscommands for some components and the same bias current adjustmentsand/or bypass commands for other components for a given phase increment.

It is to be understood that the components, configuration, and operationof the receive section is not limited to those illustrated in FIGS. 3through 5, but can include other and/or additional components,configurations, and/or operations capable of power management accordingto various embodiments.

It is further to be understood that, although the example LUTs use phaseincrements, other data associated with the touch signal frequency canalso be used.

In additional or alternative to frequency, other factors can affect theamount of noise in the touch signal. For example, the temperature oftouch components can affect the amount of noise. Higher temperatures canintroduce higher noise amounts. Higher temperatures can result in higherpower consumption because the components can operate at a higher levelto reduce more noise. Conversely, lower temperatures can result in lowerpower consumption because the components can operate at a lower level toreduce less noise. As a result, the components' power consumption canalso be affected by the temperature. Accordingly, power requirements canbe determined for various temperatures associated with correspondingnoise levels, thereby avoiding higher power consumption during lowernoise conditions.

Table 6 shows an example power management LUT, similar to LUT 554, inwhich the bias current adjustments and bypass commands can be a functionof temperature as follows.

TABLE 6 Power Management Lookup Table Example TEMP[0] IADJ_TIA[0]IADJ_BPF[0] IADJ_AAF[0] IADJ_ADC[0] BYP_BPF[0] BYP_AFF[0] TEMP[1]IADJ_TIA[1] IADJ_BPF[1] IADJ_AAF[1] IADJ_ADC[1] BYP_BPF[1] BYP_AFF[1]  

   

   

   

   

   

   

  TEMP[n] IADJ_TIA[n] IADJ_BPF[n] IADJ_AAF[n] IADJ_ADC[n] BYP_BPF[n]BYP_AFF[n]

where TEMP=the temperature of the touch components (or the ambienttemperature); IADJ_TIA=the bias current adjustment for thetransimpedence amplifier; IADJ BPF=the bias current adjustment for thebandpass filter; IADJ_AAF=the bias current adjustment for the anti-aliasfilter; IADJ_ADC=the bias current adjustment for the analog-to-digitalconverter; BYP_BPF=the bypass command for the bandpass filter; andBYP_AAF=the bypass command for the anti-alias filter. Other powermanagement LUTs based on temperature can be used, similar to LUTs 354and 454. The LUT can have a set of entries applicable to all the sensechannel components, individual entries applicable to individualcomponents, or a combination of the two.

In some embodiments, the power management LUT can be a function of bothfrequency and temperature. That is, bias current adjustments and/orbypass commands can be determined for a given frequency at a giventemperature.

In some embodiments, the power management LUT can be a function of lownoise frequency analysis, also known as spectral analysis. Duringspectral analysis, noise signals can be detected from touch componentsand analyzed at different frequencies to determine the noise magnitude.The lower noise magnitudes can indicate lower noise at those particularfrequencies, which can be deemed low noise frequencies. These low noisefrequencies can consequently be used for stimulation signals that candrive the associated touch sensor panel to generate touch signals basedon touch or near touch on the panel, thereby reducing the amount ofnoise in the touch signals. These lower noise frequencies can result inlower power consumption because the components can operate at a lowerlevel to reduce less noise. As a result, the components' powerconsumption can be affected by the low noise frequencies. Accordingly,power requirements can be determined for various low noise frequenciesassociated with corresponding noise levels, thereby avoiding higherpower consumption during lower noise conditions.

The power management LUTs 354, 454, and 554 can be used for powermanagement based on low noise frequency analysis. For example, the powermanagement logic 145 can identify the low noise frequency being used,determine the corresponding phase increment, and select thecorresponding bias current adjustments and/or bypass commands from theLUTs 354, 454, and 554 to be applied to the components of the receivesection 107 in order to manage their power consumption. Alternatively,power management LUTs, similar to LUTs 354, 454, and 554, can includethe low noise frequencies, rather than the phase increments, andcorresponding bias current adjustments and/or bypass commands.

In some embodiments, the power management LUT can be a function offrequency, temperature, and low noise frequency analysis. That is, biascurrent adjustments and/or bypass commands can be determined for a givenfrequency based on low noise frequency analysis at a given temperature.

In some embodiments, if a particular value identified by the powermanagement logic can not be matched to the power management LUT, thepower management logic can select the closest LUT entry or a default LUTentry. The power management logic can generate an error message that aLUT entry could not be applied, in which case, the touch components canoperate at either current or default power levels.

In some embodiments, the power management LUT can be replaced with astate machine, which can be partially or entirely included in orseparate from the power management logic. The state machine candynamically adjust the bias current of and/or bypass the sense channelcomponents based on a phase increment, for example. The state machinecan also dynamically adjust the bias current of and/or bypass the sensechannel components based on the amount of noise detected during the lownoise frequency analysis. For example, the state machine can receive anoise input, compare the input to a noise threshold, and dynamicallyadjust the bias current of and/or bypass the sense channel componentsbased on whether the noise exceeds the noise threshold. The statemachine can also instruct the low noise frequency analyzer to selectdifferent low noise frequencies and/or to adjust the stimulation signalfrequencies based on whether the noise exceeds the noise threshold.

In some embodiments, the power management LUT can be used in combinationwith a state machine, which can be partially or entirely included in orseparate from the power management logic. For example, the LUT caninclude ranges of bias current adjustments from low to high for thesense channel components. The state machine can select which adjustmentwithin the range to use based on certain conditions.

Other and/or additional configurations are also possible for determiningthe power management parameters to be applied to touch components,depending on the needs of the system.

FIG. 6 illustrates an exemplary method for power management of a receivesection of a touch controller according to various embodiments. In theexample of FIG. 6, current operating conditions of sense channelcomponents in the receive section of a touch controller can bedetermined (610). For example, it can be determined at what frequencyand temperature the components currently operate, whether noise has beendetected in the components and at what level, and so on. Entries in apower management LUT corresponding to one or more of the determinedconditions can be selected (620). If the entries include bias currentadjustments, the power level of the affected sense channel componentscan be adjusted based on these adjustments (625, 630). If the entriesinclude bypass commands, the affected sense channel components can bebypassed and powered down based on these commands (635, 640). If noentries are found to correspond to the determined operating conditions,an interrupt flag can be set to notify an associated processor that nocorresponding entries were found and the components can continueoperating at current conditions (645). Alternatively, the processor canintervene. In some embodiments, when no corresponding entries are found,the closest entries or default entries can be used.

FIG. 7 illustrates an exemplary demodulation section of a touchcontroller having power management according to various embodiments. Inthe example of FIG. 7, demodulation section 109 of touch controller 106can include digital demodulator 213 having programmable delay 701, mixer709, receive NCO 719, and integrator 711. The programmable delay 701 canadjust the phase of a touch signal received from a sense channel in thereceive section 107 of the touch controller 106 to correct for delayscaused by various components of the system using a component DCL 721,which can represent a sum of the system delays affecting the sensechannels. The phase-adjusted touch signal can be fed to the mixer 709 tomultiply the phase-adjusted signal with a demodulation signal generatedby the receive NCO 719 based on the numerical control input phaseincrement 764. In some embodiments, the demodulation signal can be anenvelope shaped digitally synthesized sine wave and the demodulator 213can have a bandpass filter response. The envelope (or window) of thesynthesized sine wave can be selected to reduce the stopband ripple ofthe bandpass filter response of the demodulator 213. Windows such as arectangular, Chebychev, Gaussian, etc., waveform can be used, dependingon the frequency response desired. The demodulated signal from the mixer709 can be fed to the integrator 711 to be integrated to form thecomposite touch signals, which can be stored in the result memory 215for further processing.

The integration time of the integrator 711 can affect the amount ofnoise in the touch signal. Since noise, such as white noise, can scalewith the square root of integration time, the longer the integrationtime, the lower the noise effect in the touch signal. However, longerintegration time can mean longer operation of the receive section toprovide touch signals for integration. Longer operation can in turn meanhigher power consumption. As a result, the components' power consumptioncan also be affected by the integration time. An objective of thedemodulation section 109 can be to output an acceptable touch signalquality. Therefore, the digital demodulator can balance the noise effectagainst the power consumption when there is higher signal noise. Forexample, touch components can experience both internal and externalnoise, which can typically be tolerated at a level of about 0.8% rootmean square (RMS) of the touch signal, each noise contributing about0.4% RMS, while still providing an acceptable touch signal quality.Therefore, where there is little or no external noise, the internalnoise introduced by the touch components can be allowed to increase toabout 0.8% RMS by reducing the integration time of the integrator 711.Where there is little or no internal or external noise, the integrationtime can also be reduced with little or no noise changes. Accordingly,power requirements can be determined for various integration timesassociated with corresponding noise levels, thereby avoiding higherpower consumption during lower noise conditions.

Power management LUT 754 can include data that can be used to managepower consumption of the components of the demodulation section 109. Inthe example of FIG. 7, the power management LUT 754 can includeintegration time adjustments to the integrator 711 that can be appliedso as to reduce power consumption by the integrator and consequentlypower consumption by the sense channels in the receive section of thetouch controller.

Table 7 shows an example power management LUT 754 as follows,

TABLE 7 Power Management Lookup Table Example NZ[0] TADJ_INT[0] NZ[1]TADJ_INT[1]

NZ[n] TADJ_INT[n]

where NZ=the detected noise in the touch signals; and TADJ_INT=theintegration time adjustments to the integrator.

Power management logic 145 can control which entry in the LUT 754 toselect to manage power consumption in the demodulation section 109. Thepower management logic 145 can select the integration time adjustmentfrom the LUT 754 based on the detected noise. In addition or as analternative to detected noise, the LUT 754 can include other parametersassociable with the noise to correspond to integration time adjustments,e.g., phase increment, temperature, low noise frequency analysis, and soon. The power management logic 145 can then find these parameters in theLUT 754 and select their corresponding integration time adjustments.

In an example operation, the power management logic 145 can acquire thedetected noise amount and select the corresponding integration timeadjustment from the LUT 754 to be made to the integrator 711 in order tomanage its power consumption. The integrator 711 can receive demodulatedtouch signals from the mixer 709 and integrate the signals for the timeperiod adjusted by the integration time adjustment 721.

For simplicity, FIG. 7 illustrates the details of one digitaldemodulator of the demodulation section. The demodulation section canhave multiple demodulators with similar components. As such, the powermanagement LUT can have an integration time adjustment for eachdemodulator's integrator at each given noise amount. The powermanagement LUT can alternatively have the same integration timeadjustment for all the integrators at each given noise amount. The powermanagement LUT can alternatively have individual integration timeadjustments for some integrators and shared integration time adjustmentsfor others at each given noise amount.

It is to be understood that the components, configuration, and operationof the demodulation section is not limited to those illustrated in FIG.7, but can include other and/or additional components, configurations,and/or operations capable of power management according to variousembodiments.

As previously described, the power management LUT can be replaced with astate machine or can be used in combination with a state machineaccording to various embodiments.

FIG. 8 illustrates an exemplary method for power management of ademodulation section of a touch controller according to variousembodiments. In the example of FIG. 8, current operating conditions ofdigital demodulator components in the demodulation section of a touchcontroller can be determined (810). For example, a detected noise levelin the touch signals can be determined. Alternatively, the frequency andtemperature at which the components currently operate can be determined.Entries in a power management LUT corresponding to one or more of thedetermined conditions can be selected (820). If the entries includeintegration time adjustments, the integration time of the integrator canbe adjusted based on the adjustments (830, 835). If no entries are foundto correspond to the determined operating conditions, an interrupt flagcan be set to notify an associated processor that no correspondingentries were found and the components can continue operating at currentconditions (840). Alternatively, the processor can intervene. In someembodiments, when no corresponding entries are found, the closestentries or default entries can be used.

FIG. 9 illustrates an exemplary transmit section of a touch controllerhaving power management according to various embodiments. In the exampleof FIG. 9, transmit section 114 of touch controller 106 can includetransmit digital-to-analog converter (DAC) 901 and drive channels 233that can each include analog multiplexer 903 and buffer 905. Thetransmit DAC 901 can convert digital signals from the transmit logicinto stimulation signals Vstim to supply to separate lines of bus 939.Vstim can be a positive (+) phase signal Vstim+having a waveform at thesame frequency as the transmit NCO. Vstim can also be a negative (−)phase signal Vstim− having the same waveform as Vstim+ inverted about acommon voltage Vcm. The bus 939 can also include a line carrying thecommon voltage Vcm and a line that is grounded, gnd. The multiplexer 903of the drive channel can connect to each line of the bus 939 and canselect one of the drive signals, Vstim+, Vstim−, Vcm, or gnd, to supplythe corresponding buffer 905. The multiplexer 903 can select the drivesignal based on the stimulation matrix in stimulation matrix RAM 937.The stimulation matrix can indicate which drive signal is to be appliedto which drive line of the associated touch sensor panel to stimulatethe drive lines for touch or near touch detection. The panel scan logic110 can modify the stimulation matrix. The buffer 905 of the channel cangain up the signal from the transmit DAC 901 and provide the drivecapability to drive the mostly capacitive load presented to the buffer905 by the touch sensor panel.

The frequency of the stimulation signals can affect the slew rate of thebuffers and consequently the touch signal quality. Higher frequenciescan produce higher slew rates. An objective of the drive channels in thetransmit section 114 can be to output stable stimulation signals to theassociated touch sensor panel such that resultant touch signal qualityis acceptable. Therefore, the drive channels can operate to reduce thebuffer slew rate. The components' power consumption can also be affectedby the frequency. Accordingly, power requirements can be determined forvarious frequencies associated with corresponding slew rates, therebyavoiding higher power consumption when not needed.

Power management LUT 954 can include data that can be used to managepower consumption of the components of the transmit section 114. In theexample of FIG. 9, the power management LUT 954 can include slew rateadjustments to the buffers 905 that can be applied during higherfrequencies so as to reduce power consumption to the buffers.

Table 8 shows an example power management LUT 954 as follows,

TABLE 8 Power Management Lookup Table Example DPPC[0] SRADJ_BUF[0]DPPC[1] SRADJ_BUF[1]

DPPC[n] SRADJ_BUF[n]

where DPPC=the numerical control input to the transmit NCO that canrepresent a phase increment proportional to the stimulation signalfrequency; and SRADJ_BUF=the slew rate adjustments for the buffer.

For simplicity, the power management LUT shows entries for only onebuffer. However, the transmit section can include multiple buffers. Assuch, the power management LUT can have individual slew rate adjustmentsfor each buffer for each phase increment (DPPC). The power managementLUT can alternatively have the same slew rate adjustments for all thebuffers for each phase increment. The power management LUT canalternatively have individual slew rate adjustments for some buffers andshared slew rate adjustments for others for each phase increment.

Power management logic 145 can control which entry in the LUT 954 toselect to manage power consumption of the transmit section 114. At aparticular stimulation signal frequency, the power management logic 145can identify the phase increment and select the corresponding slew rateadjustments from the LUT 954 to be applied to the buffers of thetransmit section 114 in order to manage power consumption.

In an example operation, the power management logic 145 can identifyphase increment 964 corresponding to the stimulation signal frequencyand select from the LUT 954 the slew rate adjustment to be made to thebuffer 905. The multiplexer 903 can select one of the lines of the bus939 based on data from the stimulation matrix stored in the stimulationmatrix RAM 937 and transmit the corresponding signal on the selectedline to the buffer. The buffer 905 can receive the signal from themultiplexer 903 and further prepare the signal at a power level adjustedby slew rate adjustment 915 for transmission to drive lines of theassociated touch sensor panel. The slew rate adjustments can be from nilto low to high or any combination thereof, depending on the needs of thecomponents.

As an added benefit, the slew rate adjustments can also affect the noisein the stimulation signals. For example, reducing the slew rate canreduce the signal noise. Reducing the stimulation signal frequency inorder to reduce slew rate can also reduce signal noise.

It is to be understood that the components, configuration, and operationof the transmit section is not limited to those illustrated in FIG. 9,but can include other and/or additional components, configurations,and/or operations capable of power management according to variousembodiments.

As described previously, the power management LUT can be replaced with astate machine or can be used in combination with a state machineaccording to various embodiments.

FIG. 10 illustrates an exemplary method for power management of atransmit section of a touch controller according to various embodiments.In the example of FIG. 10, current operating conditions of components inthe transmit section of a touch controller can be determined (1010). Forexample, at what frequency the components currently operate can bedetermined. Alternatively, the temperature or noise level can bedetermined. Entries in a power management LUT corresponding to one ormore of the determined conditions can be selected (1020). If the entriesinclude slew rate adjustments, the buffers can be adjusted based on theslew rate adjustments (1030, 1035). If no entries are found tocorrespond to the determined operating conditions, an interrupt flag canbe set to notify an associated processor that no corresponding entrieswere found and the components can continue operating at currentconditions (1040). Alternatively, the processor can intervene. In someembodiments, when no corresponding entries are found, the closestentries or default entries can be used.

FIG. 11 illustrates an exemplary memory section of a touch controllerhaving power management according to various embodiments. In the exampleof FIG. 11, a memory section of touch controller 106 can include decodematrix RAM 1121, which can include single stimulation decode matrix 1123and multi-stimulation decode matrix 1125, multiplexer 1105 coupled tothe decode matrix RAM, stimulation matrix RAM 1137, which can includesingle stimulation stimulation matrix 1133 and multi-stimulationstimulation matrix 1135, and multiplexor 1107 couple to the stimulationmatrix RAM. The decode matrix RAM 1121 can connect to vector operator1117 of demodulation section 109 of the touch controller 106 to providedata to the vector operator for decoding generated touch signals. Thestimulation matrix RAM 1137 can connect to the transmit sectionmultiplexors (such as multiplexor 903 in FIG. 9) of the touch controller106 to provide data to the transmit section multiplexors for generatingstimulation signals to drive the associated touch sensor panel. Thedecode matrices 1123, 1125 can be inverses of the stimulation matrices1133, 1135, respectively. The single stimulation decode matrix 1123 canbe used to decode touch signals generated based on stimulation signalsassociated with the single stimulation stimulation matrix 1133, wherethe stimulation signals were applied to one drive line at a time of theassociated touch sensor panel. The multi-stimulation decode matrix 1125can be used to decode touch signals generated based on stimulationsignals from the multi-stimulation stimulation matrix 1135, where thestimulation signals were applied simultaneously to multiple drive linesof the associated touch sensor panel. The multiplexer 1105 can selectwhich matrix 1123 or 1125 to provide to the vector operator 1117. Themultiplexer 1107 can select which matrix 1133 or 1135 to provide to thetransmit section multiplexors. Typically, the decode matrix can beselected based on the selection of the stimulation matrix. For example,selection of the single stimulation stimulation matrix 1133 can resultin selection of the single stimulation decode matrix 1123.

Generally, single stimulation can have lower power consumption thanmulti-stimulation because only one drive line can be stimulated at atime. However, single stimulation can produce lower SNR because thegenerated touch signal cannot be integrated over multiple drive lines.Therefore, selection between the multi-stimulation decode andstimulation matrix combination and the single stimulation decode andstimulation matrix combination can be done to balance power savings withnoise reduction.

Power management LUT 1154 can include data that can be used to selectwhich decode matrix to apply to the vector operator 1117 of thedemodulation section 109 and which stimulation matrix to apply to thetransmit section of the touch controller. Table 9 shows an example powermanagement LUT 1154 as follows.

TABLE 9 Power Management Lookup Table Example NZ[0] STM_DMX[0] NZ[1]STM_DMX[1]

NZ[n] STM_DMX[n]

where NZ=the detected noise in the touch signals; and STM_DMX=thecombination of stimulation matrix and decode matrix to apply.

Power management logic 145 can control which entry in the LUT 1154 toselect. The power management logic 145 can select the matrix combinationfrom the LUT 1154 based on the detected noise. In addition or as analternative to detected noise, the LUT 1154 can include other parametersassociable with the noise to correspond to the matrix selection, e.g.,phase increment, temperature, low noise frequency analysis, and so on.The power management logic 145 can then find these parameters in the LUT1154 and select the corresponding matrix combination.

In an example operation, the power management logic 145 can acquire thedetected noise amount and select the corresponding matrix selection fromthe LUT 1154. The LUT 1154 can send a selection signal to themultiplexer 1105 to select the appropriate decode matrix from the decodematrix RAM 1121 and to the multiplexor 1107 to select the appropriatestimulation matrix from the stimulation matrix RAM 1137. The selecteddecode matrix can be applied to the vector operator 1117 and theselected stimulation matrix can be applied to the transmit section.

As previously described, the LUT can be replaced with a state machine orused in combination with a state machine according to variousembodiments.

It is to be understood that the components, configuration, and operationof the memory section is not limited to those illustrated in FIG. 11,but can include other and/or additional components, configurations,and/or operations capable of power management according to variousembodiments.

FIG. 12 illustrates an exemplary method for power management of a memorysection of a touch controller according to various embodiments. In theexample of FIG. 12, current operating conditions of components in thememory section of a touch controller can be determined (1205). Forexample, the detected noise level can be determined. Alternatively, thefrequency and temperature the components at which currently operate canbe determined. Entries in a power management LUT corresponding to one ormore of the determined conditions can be selected (1215). If the entriesinclude matrix selection, the selected decode matrix and the selectedstimulation matrix can be applied (1220, 1225). If no entries are foundto correspond to the determined operating conditions, an interrupt flagcan be set to notify an associated processor that no correspondingentries were found and the components can continue operating at currentconditions (1230). Alternatively, the processor can intervene. In someembodiments, when no corresponding entries are found, the closestentries or default entries can be used.

FIGS. 13a-13e illustrate exemplary power diagrams for operating modes ofa system having touch controller power management according to variousembodiments. A touch system can have at least the following threeoperating modes: active mode, ready mode, and auto-scan mode. FIG. 13aillustrates an exemplary power diagram for an active mode without powermanagement. Example power diagrams of individual subsystems are shown.An example total composite power diagram, which is the sum of theindividual subsystems' power diagrams, is also shown. Example individualsubsystems can include a processor, an analog subsystem includingassociated logic (e.g. demodulation logic and panel scan logic), and aserial interface. Other subsystems can be included as well. As shown inthe composite power diagram, at time T0, the processor can become activeto initiate a touch sensor panel scan. At time T1, the processor cantransition into a WFI (Wait For Interrupt) state, while the channel scanlogic and the analog subsystem can actively perform a panel scan. Uponcompletion of the panel scan, at time T2, the analog subsystems cantransition into an idle state, where the analog subsystems' powerconsumption can be nearly or close to zero and the processor can wake upto process the data acquired during the panel scan. After the processorhas completed the data processing at time T3, the processor cantransition into the WFI state and initiate transfer of the processeddata via the serial interface to a host processor. At time T4, datatransfer can be completed and the serial interface can be turned off.Another panel scan can begin at time T5. Power consumption during thisactive mode can be comparable to the processor's WFI power consumptionlevel.

FIG. 13b illustrates an exemplary power diagram for an active mode withpower management. Similar to FIG. 13 a, example power diagrams for thesubsystems and the composite are shown. Prior to time TO, the system canbe in a sniff state. The sniff state power consumption can be much lowerthan the WFI power consumption because, in the sniff state, the system'shigh frequency oscillator and all associated clocks can be off. In orderfor the sniff state to be viable for the active mode, the powermanagement logic can ensure that the transition time of the touch systemfrom the active state to the sniff state is smaller than the time thesystem is in an idle state. This can allow the total current of theentire subsystem to drop low, e.g., below 100 μA in some embodiments. Incontrast, the WFI power consumption can be higher, e.g., 10 mA in someembodiments. At time T0, the channel scan logic can wake up and performa touch sensor panel scan autonomously, without intervention from theprocessor. At time T1, the analog subsystem and panel scan logic can beturned off and the processor can transition into an active state. Theprocessor can then process the data acquired by the panel scan logic.Upon completion, the processor can turn off at time T2 and transfer theprocessed data to the host processor via the serial interface. At timeT3, the touch system can transition into a sniff state. At time T4,another panel scan can begin. Power consumption during this active modewith power management can be much lower than without power management.

FIG. 13c illustrates an exemplary power diagram for a ready mode withoutpower management. This power diagram is similar to the active mode powerdiagram of FIG. 13a with the following exceptions. In the ready modepower diagram of FIG. 13 c, the panel scan duration for one scan can belonger, e.g., 40 ms for ready mode compared to 16 ms for active mode insome embodiments. Additionally, in the ready mode power diagram of FIG.13 c, at time T4, the touch system can transition into sniff state inready mode rather than into WFI state in active mode.

FIG. 13d illustrates an exemplary power diagram for a ready mode withpower management. This power diagram can be similar to the active modepower diagram of FIG. 13b with the following exception. In the readymode power diagram of FIG. 13 d, the panel scan duration for one scancan be longer, e.g., 40 ms for ready mode compared to 16 ms for activemode. Power consumption during ready mode with power management can bemuch lower than without power management.

FIG. 13e illustrates an exemplary power diagram for auto-scan mode. Attime T0, channel scan logic can initiate a touch presence scan that cancheck for a near touch or touch. The scan duration for the touchpresence scan can typically be one scan step (as opposed to multiplescan steps in active mode) until time T1 and can indicate the presencebut not the location of a near touch or touch. Another scan can begin attime T2. Because the scan duration can be much less than the scanduration during active and ready modes, power consumption can be muchlower during auto-scan mode, thereby providing power management.

FIG. 14 illustrates an exemplary composite power diagram for a systemhaving touch controller power management according to variousembodiments. Power management logic can select different power modes forthe touch system, depending on the presence of a near touch or touchcondition and/or the idle time of the system. In the example of FIG. 14,the system can begin in active mode. If a touch or near touch has notbeen detected for a certain amount of time, e.g., 16 ms in someembodiments, at time t0, the system can transition into ready mode.During ready mode, the scan duration time t ready can gradually increasewith the idle time (i.e., the time when no touches or near touches aredetected) to achieve even greater power savings until a second idle timehas reached a certain duration, e.g., 10 s in some embodiments, at timet1. At time t1, the system can transition into auto-scan mode. Duringauto-scan mode, the scan duration time t auto-scan can similarlygradually increase with the idle time until a touch or near touch isdetected at time t2. At time t2, the system can transition back intoactive mode to detect the touch or near touch. If a touch or near touchis detected, the system can transition from any low power mode (e.g.,ready mode or auto-scan mode) into the active mode.

FIG. 15 illustrates an exemplary state diagram for power managementduring operating modes of a system having touch controller powermanagement according to various embodiments. In the example of FIG. 15,the touch system can be in an active state (1550) due to the presence ofa near touch or touch condition. In the absence of a near touch or touchcondition for more than idle period TIDLE[1], the system can transitioninto a ready mode state (1551) and after another idle period TIDLE[2] toother ready mode states (and so forth) with modified scan durations. Themaximum scan durations can be a function of the particular application,e.g., an application in which touch images are acquired within a certainperiod without compromising the responsiveness and performance of thetouch subsystem. In some applications, the scan duration in ready modestate N (1553) can be at a maximum, e.g., 50 ms, where N can be aninteger. After the system has been idle for an extended time TIDLE[2+N],the system can transition into an auto-scan mode (1554) withprogressively longer scan periods in states (1555) and can enter thefinal auto-scan mode state M (1556) in which the system can reside untila near touch or touch is detected, where M can be an integer. Any neartouch or touch condition can cause the system to transition into activemode regardless of the current mode.

Table 10 shows an example listing of power modes and their associatedidle time and scan duration parameters, for example, as illustrated inFIG. 15. The processor can initialize the table at start-up based on agiven application or system requirements.

TABLE 10 Example idle times and scan durations for power modes PowerState Idle Time Scan duration Active Tidle[1] Tscan[1] Ready_1 Tidle[2]Tscan[2] . . . . . . . . . Ready_N Tidle[2 + N] Tscan[2 + N] AutoScan_1Tidle3 + N] Tscan[3 + N] . . . . . . . . . AutoScan_M Idle indefinitelyTscan[3 + N + M]

FIG. 16 illustrates an exemplary lookup table for touch controller powermanagement according to various embodiments. The example LUT showscombinations of adjustments described in the previous tables. Forexample, for a given numerical control input (DPPC) condition or noise(NZ) condition or temperature (TEMP) condition, components can beadjusted to manage their power consumption according to variousembodiments.

Although each entry in the example LUT shows only one condition and itscorresponding adjustments, it is to be understood that multipleconditions can be combined for a particular adjustment. For example, agiven numerical control input at a given noise level at a giventemperature can cause a particular adjustment to a component, whereas,that given numerical control input at another give noise level atanother given temperature can cause a different adjustment to thatcomponent. That is, the LUT can be multi-dimensional, depending on thenumbers of relatable conditions.

Certain power management functions can be active on certain devices. Assuch, in some embodiments, a common power management LUT can be used fordifferent devices with appropriate functions active and the remainderinactive. For example, a trackpad can have severe power supply noise,such that power management of its bandpass filter can be active. Adigital media player can have both power supply noise and panel noise,such that power management of its bandpass filter and its transmitbuffer can be active. A mouse can have no panel and no power supplynoise, such that power management can be inactive. Additionally certainpower management functions can be active for certain operating modes ofa device.

FIG. 17 illustrates an exemplary method for power management of a touchcontroller according to various embodiments. In the example of FIG. 17,current operating conditions and/or operating modes of components in atouch controller can be determined (1705). For example, the detectednoise level can be determined. Alternatively, the frequency andtemperature at which the components currently operate can be determined,or the mode in which the components currently operate can be determined.Entries in a power management LUT corresponding to one or more of thedetermined conditions and/or modes can be selected (1710). Based on theLUT adjustments corresponding to the entries, the components to beadjusted can be identified (1720). The adjustments can be applied to theidentified components to manage their power consumption (1725). If noentries are found to correspond to the determined operating conditionsand/or operating modes, an interrupt flag can be set to notify anassociated processor that no corresponding entries were found and thecomponents can continue operating at current conditions and/or in thecurrent modes (1730). Alternatively, the processor can intervene. Insome embodiments, when no corresponding entries are found, the closestentries or default entries can be used.

FIG. 18 illustrates an exemplary mobile telephone 1830 that can includetouch sensor panel 1824, display 1836, and other computing system blocksthat can have touch controller power management according to variousembodiments.

FIG. 19 illustrates an exemplary digital media player 1930 that caninclude touch sensor panel 1924, display 1936, and other computingsystem blocks that can have touch controller power management accordingto various embodiments.

FIG. 20 illustrates an exemplary personal computer 2030 that can includetouch sensor panel (trackpad) 2024, display 2036, and other computingsystem blocks that can have touch controller power management accordingto various embodiments.

The mobile telephone, media player, and personal computer of FIGS. 18through 20 can realize power savings with a touch controller havingpower management according to various embodiments.

Although embodiments have been fully described with reference to theaccompanying drawings, it is to be noted that various changes andmodifications will become apparent to those skilled in the art. Suchchanges and modifications are to be understood as being included withinthe scope of the various embodiments as defined by the appended claims.

What is claimed is:
 1. A method for selectively lowering powerconsumption of a touch controller device, comprising: detecting a touchsignal noise level; and based on the detected touch signal noise level,selecting a first stimulation matrix and a first decode matrixcombination; wherein the first stimulation matrix and the first decodematrix combination is selected to produce a lowest power consumptionthat exceeds a predetermined touch signal-to-noise ratio threshold. 2.The method of claim 1, wherein selecting the first stimulation matrixand the first decode matrix combination comprises selecting between asingle stimulation touch sensing operation and a multi-stimulation touchsensing combination.
 3. The method of claim 1, wherein selecting thefirst decode matrix comprises selecting between a first singlestimulation decode matrix and a first multi-stimulation decode matrix.4. The method of claim 1, wherein selecting the first stimulation matrixcomprises selecting between a first single-stimulation stimulationmatrix and a first multi-stimulation stimulation matrix.
 5. The methodof claim 1, further comprising demodulating a received touch signal inaccordance with the first decode matrix.
 6. The method of claim 1,further comprising stimulating a touch sensor panel in accordance withthe first stimulation matrix.
 7. The method of claim 1, wherein theselected first stimulation matrix and first decode matrix combinationrepresents a particular power level and a particular noise level.
 8. Themethod of claim 1, further comprising utilizing the touch signal noiselevel and a stimulation signal phase increment to select the firststimulation matrix and the first decode matrix combination.
 9. Themethod of claim 1, further comprising utilizing the touch signal noiselevel and a component temperature level to select the first stimulationmatrix and the first decode matrix combination.
 10. The method of claim1, further comprising utilizing the touch signal noise level anddetermined low noise stimulation frequency to select the firststimulation matrix and the first decode matrix combination.
 11. A touchcontroller selectively configurable for varying power consumption,comprising: a plurality of sections configured to generate or process atouch signal, each section having selectively adjustable powerconsumption; a memory configured to store a plurality of parameterscorresponding to the plurality of sections; and power management logicconfigured for detecting a touch signal noise level, and based on thedetected touch signal noise level, selecting a first stimulation matrixand a first decode matrix combination from the plurality of storedparameters, wherein the first stimulation matrix and the first decodematrix combination is selected to produce a lowest power consumption inthe plurality of sections that exceeds a predetermined touchsignal-to-noise ratio threshold.
 12. The touch controller of claim 11,the power management logic further configured for selecting between asingle stimulation touch sensing operation and a multi-stimulation touchsensing combination.
 13. The touch controller of claim 11, the powermanagement logic further configured for selecting between a first singlestimulation decode matrix and a first multi-stimulation decode matrix.14. The touch controller of claim 11, the power management logic furtherconfigured for selecting between a first single-stimulation stimulationmatrix and a first multi-stimulation stimulation matrix.
 15. The touchcontroller of claim 11, at least one of the plurality of sectionsconfigured for demodulating a received touch signal in accordance withthe first decode matrix.
 16. The touch controller of claim 11, at leastone of the plurality of sections configured for stimulating a touchsensor panel in accordance with the first stimulation matrix.
 17. Thetouch controller of claim 11, wherein the selected first stimulationmatrix and first decode matrix combination represents a particular powerlevel and a particular noise level.
 18. The touch controller of claim11, the power management logic further configured for utilizing thetouch signal noise level and a stimulation signal phase increment toselect the first stimulation matrix and the first decode matrixcombination.
 19. The touch controller of claim 11, the power managementlogic further configured for utilizing the touch signal noise level anda component temperature level to select the first stimulation matrix andthe first decode matrix combination.
 20. The touch controller of claim11, the power management logic further configured for utilizing thetouch signal noise level and determined low noise stimulation frequencyto select the first stimulation matrix and the first decode matrixcombination.